Wildfire-induced air pollution may increase risk of cardiac arrests: Study

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Researchers have revealed that air pollution caused by wildfires may increase the risk of cardiac arrests and other sudden acute heart problems in people living near areas that are prone to frequent wildfires.

The study, carried out by a team of researchers led by Dr Anjali Haikerwal, Department of Epidemiology and Preventive Medicine at Monash University, examines the association between exposure to tiny particulate pollutants found in wildfire smoke and the risk of heart-related incidents in the state of Victoria between December 2006 and January 2007.

Researchers say that while there have been quite a few studies that look at association between wildfire smoke and respiratory problems, few have looked at an association between wildfire smoke exposure and heart problems.

In the new study, researchers found that during the period between December 2006 and January 2007, smoke reached cities far from the blazes and on most days the levels of fine particulate air pollutant exceeded recommended air quality limits.

The particles studied by researchers were smaller than 2.5 thousandths of a millimetre in diameter, which is significantly smaller than a speck of dust or 1/30th diameter of a human hair, and typically not visible to the human eye.

Using data from the Victorian Ambulance Cardiac Arrest Registry from Ambulance Victoria and data from the Department of Health and Human Services, researchers found that for an increase from the 25th to 75th percentile in particulate concentration over two days, after adjusting for temperature and humidity, there was a:

  • 6.98 per cent increase in out-of-hospital cardiac arrests, with a stronger association between pollution and cardiac arrests in men and people 65 and older;
  • 2.07 per cent increase in emergency department visits for acute cardiac events;
  • 1.86 per cent increase in hospitalisations for acute cardiac events, with a stronger association in women and people 65 and older.

Dr Haikerwal suggests that the particles in air may be one of the triggers for acute cardiovascular events and anyone experiencing symptoms of heart problems during smoke episodes from wildfires should seek immediate medical attention.

Fine particulate matter may be the most common and hazardous type of air pollution. Besides burning wood, it also comes from burning coal, car exhaust and other sources. Given the increase in frequency and intensity of wildfires experienced worldwide in recent years, Dr Haikerwal said it’s important to understand the impact of wildfire smoke exposure on acute health effects in the community.

“During a fire, please take precautionary measures as advised by public health officials,” Dr Haikerwal said.

“This is especially important for older adults who are at higher risk of adverse health effects during wildfire smoke exposure.”